Abstract: The invention relates to secondary power system apparatus and method for use aboard aircraft in place of conventional auxiliary power units (APU's) and emergency power units (EPU's). The invention integrated power unit (IPU) performs the function of both an APU and an EPU, while avoiding the use of hazardous monofuels. The IPU includes a turbine engine operable on pressurized ambient air, or on pressurized stored air, along with jet engine fuel. The structure of a combustion chamber for the engine which is able to use pressurized air from two separate sources; of a control able to selectively operate the engine as an EPU, as an APU, and to effect operating transition from EPU to APU; and of a composite secondary power system with the IPU are all disclosed.

Abstract: a balanced butterfly valve method and apparatus having a valve plate pivotally supported within a mounting body. The valve plate is capable of both rotational and translational movement in response to rotation of an input shaft. A spring is provided to resist translational movement of the valve plate. Differential gearing is used to convert rotational movement of the input shaft into rotational and translational movement of the valve plate depending on the relationship between the force exerted by the spring and the torque exerted on the valve plate by the fluid.